As shown in FIG. 1, a door opening and closing apparatus for a construction machine in accordance with the prior art includes a hinge 2 consisting of a first hinge unit 2a mounted on an operator's cab 1 and a second hinge unit 2b mounted on a door 3 so as to perform a relative rotation with respect to the upper hinge unit 2a so that the door 3 can be opened or closed by the hinge 2. A handrail is mounted on the operator's cab 1 so that the door 3 can be opened or closed. In case of a small-sized construction machine, the inner space of the operator's cab 1 is small, and thus the handrail cannot be mounted on the operator's cab 1.
The above-mentioned hinge 2 has an advantage in that the manufacturing cost is decreased and its manufacture is easy due to simplicity of structure. On the other hand, in the case where the door 3 is opened at a maximum angle, the door 3 is far away from an entrance of the operator's cab 1.
For this reason, an operator suffers from an inconvenience of having to sticking a part of his or her body out of the operator's cab 1 in order for the operator in the operator's cab 1 to close the door 3. In addition, the conventional door opening and closing apparatus for a construction machine entails a problem in that the operator loses a body balance during the closing the door 3 and thus falls down from an operator's seat, which cause an injury to him or her.